RESUMEN
Brain changes have been reported in the first weeks after SARS-CoV-2 infection. However, limited literature exists about brain alterations in post-COVID syndrome, a condition increasingly associated with cognitive impairment. The present study aimed to evaluate brain functional and structural alterations in patients with post-COVID syndrome, and assess whether these brain alterations were related to cognitive dysfunction. Eighty-six patients with post-COVID syndrome and 36 healthy controls were recruited and underwent neuroimaging acquisition and a comprehensive neuropsychological assessment. Cognitive and neuroimaging examinations were performed 11 months after the first symptoms of SARS-CoV-2. Whole-brain functional connectivity analysis was performed. Voxel-based morphometry was performed to evaluate grey matter volume, and diffusion tensor imaging was carried out to analyse white-matter alterations. Correlations between cognition and brain changes were conducted and Bonferroni corrected. Post-COVID syndrome patients presented with functional connectivity changes, characterized by hypoconnectivity between left and right parahippocampal areas, and between bilateral orbitofrontal and cerebellar areas compared to controls. These alterations were accompanied by reduced grey matter volume in cortical, limbic and cerebellar areas, and alterations in white matter axial and mean diffusivity. Grey matter volume loss showed significant associations with cognitive dysfunction. These cognitive and brain alterations were more pronounced in hospitalized patients compared to non-hospitalized patients. No associations with vaccination status were found. The present study shows persistent structural and functional brain abnormalities 11 months after the acute infection. These changes are associated with cognitive dysfunction and contribute to a better understanding of the pathophysiology of the post-COVID syndrome.
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COVID-19 , Sustancia Blanca , Humanos , Imagen de Difusión Tensora/métodos , Imagen por Resonancia Magnética/métodos , SARS-CoV-2 , Encéfalo , Neuroimagen/métodos , Cognición/fisiología , Sustancia Gris , SíndromeRESUMEN
Over the past thirty years, research has shown the huge potential of chitosan in biomedical applications such as drug delivery, tissue engineering and regeneration, cancer therapy, and antimicrobial treatments, among others. One of the major advantages of this interesting polysaccharide is its modifiability, which facilitates its use in tailor-made applications. In this way, the molecular structure of chitosan has been conjugated with multiple molecules to modify its mechanical, biological, or chemical properties. Here, we review the conjugation of chitosan with some bioactive molecules: hydroxycinnamic acids (HCAs); since these derivatives have been probed to enhance some of the biological effects of chitosan and to fine-tune its characteristics for its application in the biomedical field. First, the main characteristics of chitosan and HCAs are presented; then, the currently employed conjugation strategies between chitosan and HCAs are described; and, finally, the studied biomedical applications of these derivatives are discussed to present their limitations and advantages, which could lead to proximal therapeutic uses.
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Antiinfecciosos , Quitosano , Quitosano/química , Materiales Biocompatibles/química , Ácidos Cumáricos/uso terapéutico , Ingeniería de Tejidos , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Antiinfecciosos/químicaRESUMEN
It has been suggested that some individuals may present genetic susceptibility to SARS-CoV-2 infection, with particular research interest in variants of the ACE2 and TMPRSS2 genes, involved in viral penetration into cells, in different populations and geographic regions, although insufficient information is currently available. This study addresses the apparently reasonable hypothesis that variants of these genes may modulate viral infectivity, making some individuals more vulnerable than others. Through whole-exome sequencing, the frequency of exonic variants of the ACE2, TMPRSS2, and Furin genes was analyzed in relation to presence or absence of SARS-CoV-2 infection in a familial multiple sclerosis cohort including 120 individuals from Madrid. The ACE2 gene showed a low level of polymorphism, and none variant was significantly associated with SARS-CoV-2 infection. These variants have previously been detected in Italy. While TMPRSS2 is highly polymorphic, the variants found do not coincide with those described in other studies, with the exception of rs75603675, which may be associated with SARS-CoV-2 infection. The synonymous variants rs61735792 and rs61735794 showed a significant association with infection. Despite the limited number of patients with SARS-CoV-2 infection, some variants, especially in TMPRSS2, may be associated with COVID-19.
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Enzima Convertidora de Angiotensina 2/genética , COVID-19/genética , Furina/genética , Esclerosis Múltiple/genética , Receptores Virales/genética , Serina Endopeptidasas/genética , Enzima Convertidora de Angiotensina 2/metabolismo , COVID-19/metabolismo , COVID-19/virología , Estudios de Cohortes , Furina/metabolismo , Expresión Génica , Predisposición Genética a la Enfermedad , Interacciones Huésped-Patógeno/genética , Humanos , Esclerosis Múltiple/metabolismo , Esclerosis Múltiple/virología , Polimorfismo Genético , Unión Proteica , Receptores Virales/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidad , Serina Endopeptidasas/metabolismo , España , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Encuestas y Cuestionarios , Internalización del Virus , Secuenciación del ExomaRESUMEN
INTRODUCTION: AQP4 (aquaporin-4)-immunoglobulin G (IgG)-mediated neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease that affects the central nervous system, particularly the spinal cord and optic nerve; remyelination capacity in neuromyelitis optica is yet to be determined, as is the role of AQP4-IgG in cell differentiation. MATERIAL AND METHODS: We included three groups-a group of patients with AQP4-IgG-positive neuromyelitis optica, a healthy group, and a sham group. We analyzed differentiation capacity in cultures of neurospheres from the subventricular zone of mice by adding serum at two different times: early and advanced stages of differentiation. We also analyzed differentiation into different cell lines. RESULTS AND CONCLUSIONS: The effect of sera from patients with NMOSD on precursor cells differs according to the degree of differentiation, and probably affects oligodendrocyte progenitor cells from NG2 cells to a lesser extent than cells from the subventricular zone; however, the resulting oligodendrocytes may be compromised in terms of maturation and possibly limited in their ability to generate myelin. Furthermore, these cells decrease in number with age. It is very unlikely that the use of drugs favoring the migration and differentiation of oligodendrocyte progenitor cells in multiple sclerosis would be effective in the context of neuromyelitis optica, but cell therapy with oligodendrocyte progenitor cells seems to be a potential alternative.
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Acuaporina 4/inmunología , Autoanticuerpos/inmunología , Diferenciación Celular , Sistema Nervioso Central/patología , Inmunoglobulina G/inmunología , Neuromielitis Óptica/inmunología , Células Precursoras de Oligodendrocitos/patología , Animales , Autoanticuerpos/sangre , Estudios de Casos y Controles , Sistema Nervioso Central/inmunología , Cerebelo/inmunología , Cerebelo/patología , Femenino , Humanos , Masculino , Ratones Endogámicos BALB C , Persona de Mediana Edad , Neuromielitis Óptica/sangre , Neuromielitis Óptica/patología , Células Precursoras de Oligodendrocitos/inmunologíaRESUMEN
Oligodendrocyte precursor cell (OPC) migration is a mechanism involved in remyelination; these cells migrate from niches in the adult CNS. However, age and disease reduce the pool of OPCs; as a result, the remyelination capacity of the CNS decreases over time. Several experimental studies have introduced OPCs to the brain via direct injection or intrathecal administration. In this study, we used the nose-to brain pathway to deliver oligodendrocyte lineage cells (human oligodendroglioma (HOG) cells), which behave similarly to OPCs in vitro. To this end, we administered GFP-labelled HOG cells intranasally to experimental animals, which were subsequently euthanised at 30 or 60 days. Our results show that the intranasal route is a viable route to the CNS and that HOG cells administered intranasally migrate preferentially to niches of OPCs (clusters created during embryonic development and adult life). Our study provides evidence, albeit limited, that HOG cells either form clusters or adhere to clusters of OPCs in the brains of experimental animals.
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Encéfalo/fisiología , Enfermedades Desmielinizantes/terapia , Células Precursoras de Oligodendrocitos/citología , Oligodendroglioma/química , Remielinización , Células Madre/citología , Administración Intranasal , Animales , Encéfalo/citología , Diferenciación Celular , Células Cultivadas , HumanosRESUMEN
INTRODUCTION: Stroke represents an attractive target for cell therapy. Although different types of cells have been employed in animal models with variable results, the human adipose-derived stem cells (hASCs) have demonstrated favorable characteristics in the treatment of diseases with inflammatory substrate, but experience in their intracerebral administration is lacking. The purpose of this study is to evaluate the effect and safety of the intracerebral application of hASCs in a stroke model. METHODS: A first group of Athymic Nude mice after stroke received a stereotactic injection of hASCs at a concentration of 4 × 104/µL at the penumbra area, a second group without stroke received the same cell concentration, and a third group had only stroke and no cells. After 7, 15, and 30 days, the animals underwent fluorodeoxyglucose-positron emission tomography and magnetic resonance imaging; subsequently, they were sacrificed for histological evaluation (HuNu, GFAP, IBA-1, Ki67, DCX) of the penumbra area and ipsilateral subventricular zone (iSVZ). RESULTS: The in vitro studies found no alterations in the molecular karyotype, clonogenic capacity, and expression of 62 kDa transcription factor and telomerase. Animals implanted with cells showed no adverse events. The implanted cells showed no evidence of proliferation or differentiation. However, there was an increase of capillaries, less astrocytes and microglia, and increased bromodeoxyuridine and doublecortin-positive cells in the iSVZ and in the vicinity of ischemic injury. CONCLUSIONS: These results suggest that hASCs in the implanted dose modulate inflammation, promote endogenous neurogenesis, and do not proliferate or migrate in the brain. These data confirm the safety of cell therapy with hASCs.
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Isquemia Encefálica/terapia , Trasplante de Células Madre , Tejido Adiposo/citología , Animales , Encéfalo/irrigación sanguínea , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Encéfalo/patología , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Proliferación Celular , Modelos Animales de Enfermedad , Proteína Doblecortina , Gliosis/diagnóstico por imagen , Gliosis/metabolismo , Gliosis/patología , Gliosis/terapia , Humanos , Masculino , Ratones Desnudos , Microglía/metabolismo , Microglía/patología , Actividad Motora , Neovascularización Patológica/diagnóstico por imagen , Neovascularización Patológica/metabolismo , Neovascularización Patológica/patología , Neovascularización Patológica/terapia , Neuronas/metabolismo , Neuronas/patología , Distribución Aleatoria , Trasplante de Células Madre/efectos adversos , Células Madre/citología , Trasplante HeterólogoRESUMEN
BACKGROUND: Adult neurogenesis persists through life at least in classic neurogenic niches. Neurogenesis has been previously described as reduced in neurodegenerative diseases. There is not much knowledge about is adult neurogenesis is or not modified in amyotrophy lateral sclerosis (ALS). All previous publications has studied the ALS SOD1 (superoxide dismutase) transgenic mouse model. The purpose of this study is to examine the process of adult neurogenesis in classic niches (subventricular zone [SVZ] and subgranular zone [SGZ] of the dentate gyrus) in patients with amyotrophic lateral sclerosis (ALS), both with (ALS-FTD) and without associated frontotemporal dementia (FTD). METHODS: We studied 9 autopsies of patients with ALS (including 2 with ALS-FTD) and 4 controls. ALS was confirmed histologically. Studies of the SVZ and SGZ were conducted using markers of proliferation (Ki-67, PCNA), of pluripotent neural progenitor cells (GFAPδ), neuroblasts (PSA-NCAM, DCX, TUJ1), and an astrocyte marker (GFAP). Results were analyzed with non-parametric tests. We then studied correlations between the different markers and the percentage of phosphorylated TDP-43 (pTDP-43). RESULTS: We observed a statistically significant increase in proliferation in the SVZ in all patients with ALS. While this increase was more marked in ALS forms associated with dementia, the small sample size does not permit a statistical subgroup analysis. In contrast, proliferation in the SGZ was decreased in all patients. These alterations showed a positive and direct correlation with the percentage of pTDP-43 in the SVZ, and a negative, exponential correlation with that percentage in the SGZ. CONCLUSIONS: We observed alterations of the proliferation of neural progenitor in classic adult neurogenic niches in patients with ALS. The 2 neurogenic niches exhibited opposite changes such that proliferation increased in the SVZ and decreased in the SGZ.
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Esclerosis Amiotrófica Lateral/fisiopatología , Encéfalo/fisiopatología , Demencia Frontotemporal/fisiopatología , Anciano , Anciano de 80 o más Años , Encéfalo/patología , Proteína Doblecortina , Femenino , Humanos , Ventrículos Laterales , Masculino , Persona de Mediana Edad , Células-Madre Neurales/metabolismo , Neurogénesis/fisiologíaRESUMEN
We reported that the ethanol-induced innate immune response by activating TLR4 signaling triggers gliosis and neuroinflammation. Ethanol also activates other immune receptors, such as NOD-like-receptors, and specifically NLRP3-inflammasome in astroglial cells, to stimulate caspase-1 cleavage and IL-1ß and IL-18 cytokines production. Yet, whether microglia NLRs are also sensitive to the ethanol effects that contribute to neuroinflammation is uncertain. Using cerebral cortexes of the chronic alcohol-fed WT and TLR4(-/-) mice, we demonstrated that chronic ethanol treatment enhanced TLR4 mediated-NLRP3/Caspase-1 complex activation, and up-regulated pro-inflammatory cytokines and chemokines levels. Ethanol-induced NLRP3-inflammasome activation and mitochondria-ROS generation were also observed in cultured microglial cells. The up-regulation of CD45(high)/CD11b(+) cell populations and matrix metalloproteinase-9 levels was also noted in the cortexes of the ethanol-treated WT mice. Notably, elimination of the TLR4 function abolished most ethanol-induced neuroinflammatory effects. Thus, our results demonstrate that ethanol triggers TLR4-mediated NLRP3-inflammasome activation in glial cells, and suggest that microglia stimulation may compromise the permeability of blood-brain barrier events to contribute to ethanol-induced neuroinflammation and brain damage.
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Barrera Hematoencefálica , Proteínas Portadoras/fisiología , Etanol/toxicidad , Leucocitos/citología , Microglía/efectos de los fármacos , Receptor Toll-Like 4/fisiología , Animales , Sistema Nervioso Central/citología , Sistema Nervioso Central/efectos de los fármacos , Femenino , Ratones , Ratones Endogámicos C57BL , Microglía/citología , Proteína con Dominio Pirina 3 de la Familia NLRRESUMEN
Despite recent advances in the development of new cancer therapies, the treatment options for glioma remain limited, and the survival rate of patients has changed little over the past three decades. Here, we show that 2-hydroxyoleic acid (2OHOA) induces differentiation and autophagy of human glioma cells. Compared to the current reference drug for this condition, temozolomide (TMZ), 2OHOA combated glioma more efficiently and, unlike TMZ, tumor relapse was not observed following 2OHOA treatment. The novel mechanism of action of 2OHOA is associated with important changes in membrane-lipid composition, primarily a recovery of sphingomyelin (SM) levels, which is markedly low in glioma cells before treatment. Parallel to membrane-lipid regulation, treatment with 2OHOA induced a dramatic translocation of Ras from the membrane to the cytoplasm, which inhibited the MAP kinase pathway, reduced activity of the PI3K/Akt pathway, and downregulated Cyclin D-CDK4/6 proteins followed by hypophosphorylation of the retinoblastoma protein (RB). These regulatory effects were associated with induction of glioma cell differentiation into mature glial cells followed by autophagic cell death. Given its high efficacy, low toxicity, ease of oral administration, and good distribution to the brain, 2OHOA constitutes a new and potentially valuable therapeutic tool for glioma patients.
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Antineoplásicos/farmacología , Autofagia/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Glioma/tratamiento farmacológico , Ácidos Oléicos/farmacología , Animales , Antineoplásicos/metabolismo , Línea Celular Tumoral , Membrana Celular/química , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Dacarbazina/análogos & derivados , Dacarbazina/farmacología , Relación Dosis-Respuesta a Droga , Glioma/metabolismo , Glioma/patología , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Lípidos de la Membrana/química , Lípidos de la Membrana/metabolismo , Ratones , Ratones Desnudos , Microscopía Confocal , Ácidos Oléicos/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Transporte de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Temozolomida , Factores de Tiempo , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas ras/metabolismoRESUMEN
In a recent study we found that cerebrospinal fluids (CSFs) from amyotrophic lateral sclerosis (ALS) patients caused 20-30% loss of cell viability in primary cultures of rat embryo motor cortex neurons. We also found that the antioxidant resveratrol protected against such damaging effects and that, surprisingly, riluzole antagonized its protecting effects. Here we have extended this study to the interactions of riluzole with 3 other recognized neuroprotective agents, namely memantine, minocycline and lithium. We found: (1) by itself riluzole exerted neurotoxic effects at concentrations of 3-30 µM; this cell damage was similar to that elicited by 30 µM glutamate and a 10% dilution of ALS/CSF; (2) memantine (0.1-30 µM), minocycline (0.03-1 µM) and lithium (1-80 µg/ml) afforded 10-30% protection against ALS/CSF-elicited neurotoxicity, and (3) at 1-10 µM, riluzole antagonized the protection afforded by the 3 agents. These results strongly support the view that at the riluzole concentrations reached in the brain of patients, the neurotoxic effects of this drug could be masking the potential neuroprotective actions of new compounds being tested in clinical trials. Therefore, in the light of the present results, the inclusion of a group of patients free of riluzole treatment may be mandatory in future clinical trials performed in ALS patients with novel neuroprotective compounds.
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Esclerosis Amiotrófica Lateral/líquido cefalorraquídeo , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Riluzol/toxicidad , Animales , Supervivencia Celular/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores/toxicidad , Humanos , Litio/farmacología , Memantina/farmacología , Minociclina/farmacología , RatasRESUMEN
The main objective was to evaluate structural and functional connectivity correlates of fatigue in post-COVID syndrome, and to investigate the relationships with an objective measure of mental fatigue and with subjective cognitive complaints. One-hundred and twenty-nine patients were recruited after 14.79 ± 7.17 months. Patients were evaluated with fatigue, neuropsychological, and subjective cognitive complaints assessments. Structural and functional magnetic resonance imaging were acquired, and functional connectivity, white matter diffusivity and grey matter volume were evaluated. Fatigue was present in 86 % of patients, and was highly correlated to subjective cognitive complaints. Fatigue was associated with structural and functional connectivity mostly in frontal areas but also temporal, and cerebellar areas, showing mental fatigue different pattern of functional connectivity correlates compared to physical fatigue. White matter diffusivity correlates were similar in fatigue and subjective cognitive complaints, located in the forceps minor, anterior corona radiata and anterior cingulum. Findings confirm that fatigue in post-COVID syndrome is related to cerebral connectivity patterns, evidencing its brain substrates. Moreover, results highlight the relationship between fatigue and subjective cognitive complaints. These findings point out the relevance of the multidisciplinary assessment of post-COVID syndrome patients with subjective cognitive complaints, in order to unravel the symptomatology beneath the patient's complaints.
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Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by significant metabolic disruptions, including weight loss and hypermetabolism in both patients and animal models. Leptin, an adipose-derived hormone, displays altered levels in ALS. Genetically reducing leptin levels (Lepob/+) to maintain body weight improved motor performance and extended survival in female SOD1G93A mice, although the exact molecular mechanisms behind these effects remain elusive. Here, we corroborated the sexual dimorphism in circulating leptin levels in ALS patients and in SOD1G93A mice. We reproduced a previous strategy to generate a genetically deficient leptin SOD1G93A mice (SOD1G93ALepob/+) and studied the transcriptomic profile in the subcutaneous adipose tissue and the spinal cord. We found that leptin deficiency reduced the inflammation pathways activated by the SOD1G93A mutation in the adipose tissue, but not in the spinal cord. These findings emphasize the importance of considering sex-specific approaches in metabolic therapies and highlight the role of leptin in the systemic modulation of ALS by regulating immune responses outside the central nervous system.
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Esclerosis Amiotrófica Lateral , Animales , Femenino , Humanos , Masculino , Ratones , Tejido Adiposo/metabolismo , Esclerosis Amiotrófica Lateral/metabolismo , Modelos Animales de Enfermedad , Haploinsuficiencia , Leptina/metabolismo , Ratones Transgénicos , Médula Espinal/metabolismo , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/metabolismoRESUMEN
Inherited retinal degenerations affecting both rod and cone photoreceptors constitute one of the causes of incurable blindness in the developed world. Cyclic guanosine monophosphate (cGMP) is crucial in the phototransduction and, mutations in genes related to its metabolism are responsible for different retinal dystrophies. cGMP-degrading phosphodiesterase 6 (PDE6) mutations cause around 4-5% of the retinitis pigmentosa, a rare form of retinal degeneration. The aim of this study was to evaluate whether pharmacological PDE6 inhibition induced retinal degeneration in cone-enriched cultures of porcine retina similar to that found in murine models. PDE6 inhibition was induced in cone-enriched retinal explants from pigs by Zaprinast. PDE6 inhibition induced cGMP accumulation and triggered retinal degeneration, as determined by TUNEL assay. Western blot analysis and immunostaining indicated that degeneration was accompanied by caspase-3, calpain-2 activation and poly (ADP-ribose) accumulation. Oxidative stress markers, total antioxidant capacity, thiobarbituric acid reactive substances (TBARS) and nitric oxide measurements revealed the presence of oxidative damage. Elevated TNF-alpha and IL-6, as determined by enzyme immunoassay, were also found in cone-enriched retinal explants treated with Zaprinast. Our study suggests that this ex vivo model of retinal degeneration in porcine retina could be an alternative model for therapeutic research into the mechanisms of photoreceptor death in cone-related diseases, thus replacing or reducing animal experiments.
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Estrés Oxidativo/efectos de los fármacos , Inhibidores de Fosfodiesterasa/farmacología , Purinonas/farmacología , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Degeneración Retiniana/inducido químicamente , Retinitis Pigmentosa/inducido químicamente , Animales , Apoptosis/efectos de los fármacos , Calpaína/metabolismo , Caspasa 3/metabolismo , GMP Cíclico/metabolismo , Etiquetado Corte-Fin in Situ , Técnicas de Cultivo de Órganos , Células Fotorreceptoras Retinianas Conos/patología , Degeneración Retiniana/inmunología , Degeneración Retiniana/metabolismo , Retinitis Pigmentosa/inmunología , Retinitis Pigmentosa/metabolismo , Porcinos , Porcinos EnanosRESUMEN
It has been demonstrated that the exposure of biological systems to magnetic fields (MFs) can produce several beneficial effects: tissue recovery in chronic wounds, re-establishment of blood circulation after tissue ischemia or in necrotic tissues, improvement after epileptic episodes, angiogenesis, etc. In the current study, the effects of extremely low frequency (ELF) MF on the capillaries of some circumventricular organs (CVOs) are demonstrated; a vasodilator effect is reported as well as an increase in their permeability to non-liposoluble substances. For this study, 96 Wistar male rats (250 g body mass) were used and divided into three groups of 32 rats each: a control group (no treatment); a sham ELF-MF group; and an experimental group subjected to ELF-MF (120 Hz harmonic waves and 0.66 mT, root mean square) by the use of Helmholtz coils. All animals were administered colloidal carbon (CC) intravenously to study, through optical and transmission electron microscopy, the capillary permeability in CVOs and the blood-brain barrier (BBB) in brain areas. An increase in capillary permeability to CC was detected in the ELF-MF-exposed group as well as a significant increase in vascular area (capillary vasodilation); none of these effects were observed in individuals of the control and sham ELF-MF groups. It is important to investigate the mechanisms involved in the phenomena reported here in order to explain the effects of ELF-MF on brain vasculature.
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Barrera Hematoencefálica/fisiología , Capilares/efectos de la radiación , Permeabilidad Capilar/efectos de la radiación , Campos Magnéticos , Animales , Barrera Hematoencefálica/efectos de la radiación , Carbono , Ventrículos Cerebrales/irrigación sanguínea , Ventrículos Cerebrales/efectos de la radiación , Masculino , Ratas , Ratas WistarRESUMEN
The implantation of oligodendrocyte precursor cells may be a useful therapeutic strategy for targeting remyelination. However, it is yet to be established how these cells behave after implantation and whether they retain the capacity to proliferate or differentiate into myelin-forming oligodendrocytes. One essential issue is the creation of administration protocols and determining which factors need to be well established. There is controversy around whether these cells may be implanted simultaneously with corticosteroid treatment, which is widely used in many clinical situations. This study assesses the influence of corticosteroids on the capacity for proliferation and differentiation and the survival of human oligodendroglioma cells. Our findings show that corticosteroids reduce the capacity of these cells to proliferate and to differentiate into oligodendrocytes and decrease cell survival. Thus, their effect does not favour remyelination; this is consistent with the results of studies with rodent cells. In conclusion, protocols for the administration of oligodendrocyte lineage cells with the aim of repopulating oligodendroglial niches or repairing demyelinated axons should not include corticosteroids, given the evidence that the effects of these drugs may undermine the objectives of cell transplantation.
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Metilprednisolona , Oligodendroglía , Humanos , Metilprednisolona/farmacología , Vaina de Mielina , Axones , Diferenciación CelularRESUMEN
One of the main concerns related to SARS-CoV-2 infection is the symptoms that could be developed by survivors, known as long COVID, a syndrome characterized by persistent symptoms beyond the acute phase of the infection. This syndrome has emerged as a complex and debilitating condition with a diverse range of manifestations affecting multiple organ systems. It is increasingly recognized for affecting the Central Nervous System, in which one of the most prevalent manifestations is cognitive impairment. The search for effective therapeutic interventions has led to growing interest in Mesenchymal Stem Cell (MSC)-based therapies due to their immunomodulatory, anti-inflammatory, and tissue regenerative properties. This review provides a comprehensive analysis of the current understanding and potential applications of MSC-based interventions in the context of post-acute neurological COVID-19 syndrome, exploring the underlying mechanisms by which MSCs exert their effects on neuroinflammation, neuroprotection, and neural tissue repair. Moreover, we discuss the challenges and considerations specific to employing MSC-based therapies, including optimal delivery methods, and functional treatment enhancements.
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COVID-19 , Células Madre Mesenquimatosas , Humanos , COVID-19/terapia , SARS-CoV-2 , Síndrome Post Agudo de COVID-19 , Células Madre Mesenquimatosas/fisiología , Sistema Nervioso CentralRESUMEN
BACKGROUND: Cognitive deficits are among the main disabling symptoms in COVID-19 patients and post-COVID syndrome (PCS). Within brain regions, the hippocampus, a key region for cognition, has shown vulnerability to SARS-CoV-2 infection. Therefore, in vivo detailed evaluation of hippocampal changes in PCS patients, validated on post-mortem samples of COVID-19 patients at the acute phase, would shed light into the relationship between COVID-19 and cognition. METHODS: Hippocampal subfields volume, microstructure, and perfusion were evaluated in 84 PCS patients and compared to 33 controls. Associations with blood biomarkers, including glial fibrillary acidic protein (GFAP), myelin oligodendrocyte glycoprotein (MOG), eotaxin-1 (CCL11) and neurofilament light chain (NfL) were evaluated. Besides, biomarker immunodetection in seven hippocampal necropsies of patients at the acute phase were contrasted against eight controls. FINDINGS: In vivo analyses revealed that hippocampal grey matter atrophy is accompanied by altered microstructural integrity, hypoperfusion, and functional connectivity changes in PCS patients. Hippocampal structural and functional alterations were related to cognitive dysfunction, particularly attention and memory. GFAP, MOG, CCL11 and NfL biomarkers revealed alterations in PCS, and showed associations with hippocampal volume changes, in selective hippocampal subfields. Moreover, post mortem histology showed the presence of increased GFAP and CCL11 and reduced MOG concentrations in the hippocampus in post-mortem samples at the acute phase. INTERPRETATION: The current results evidenced that PCS patients with cognitive sequalae present brain alterations related to cognitive dysfunction, accompanied by a cascade of pathological alterations in blood biomarkers, indicating axonal damage, astrocyte alterations, neuronal injury, and myelin changes that are already present from the acute phase. FUNDING: Nominative Grant FIBHCSC 2020 COVID-19. Department of Health, Community of Madrid. Instituto de Salud Carlos III through the project INT20/00079, co-funded by European Regional Development Fund "A way to make Europe" (JAMG). Instituto de Salud Carlos III (ISCIII) through Sara Borrell postdoctoral fellowship Grant No. CD22/00043) and co-funded by the European Union (MDC). Instituto de Salud Carlos III through a predoctoral contract (FI20/000145) (co-funded by European Regional Development Fund "A way to make Europe") (MVS). Fundación para el Conocimiento Madri+d through the project G63-HEALTHSTARPLUS-HSP4 (JAMG, SOM).
Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Hipocampo/patología , Atrofia , Síndrome , BiomarcadoresRESUMEN
Alcohol abuse and alcoholism can cause brain damage, loss of white matter, myelin fiber disruption, and even neuronal injury. The underlying mechanisms of these alterations remain elusive. We have shown that chronic ethanol intake, by activating glial toll-like receptor 4 (TLR4) receptors, triggers the production of inflammatory mediators and can cause brain damage. Because neuroinflammation may be associated with demyelination and neuronal damage, we evaluate whether the ethanol-induced TLR4-dependent proinflammatory environment in the brain could be involved in the myelin disruptions observed in alcoholics. Using brains from wild-type (WT) and TLR4 knockout (KO, TLR4(-/-) ) mice, we demonstrate that chronic ethanol treatment downregulated proteins involved in myelination [proteolipid protein (PLP), myelin basic protein (MBP), myelin-oligodendrocyte glycoprotein, 2,3-cyclic-nucleotide-3-phosphodiesterase, and myelin-associated glycoprotein], while increased chondroitin sulfate proteoglycan NG2 (NG2)-proteoglycan in several brain regions of ethanol-treated WT mice. The immunohistochemistry analysis also revealed that ethanol-treatment-altered myelin morphology reduced the number of MBP-positive fibers and caused oligodendrocyte death, as demonstrated by an increase in caspase-3-positive oligodendrocytes. The in vivo imaging system further confirmed that chronic ethanol intake markedly reduced the PLP in WT mice. Most myelin alterations were not observed in brains from ethanol-treated TLR4(-/-) mice. Electron microscopy studies revealed that although 41-47% of axons showed myelin sheath disarrangements in the cerebral cortex and corpus callosum of WT ethanol-treated mice, respectively, small focal fiber disruptions were noticed in these brain areas of ethanol-treated TLR4(-/-) mice. In summary, the present results suggest that ethanol-induced neuroinflammation might be involved in myelin disruptions and white matter loss observed in human alcoholics.